Overview
In Project settings administrator may find an Issue approval panel. This panel contains a number of settings to enable and adjust approval process in the project.
Go to Project settings → Issue approval
There are 3 tabs in Issue approval panel:
Configuration - allows creating configurations for approvals
Notification - additional notification settings
Requests - list of all requests in current project
Configuration
Before creating configuration per issue types, there is a block with optional settings that define some general approval aspects:
Who can request approvals
By default any issue assignee can request approval in issue. With this setting, you can create a rule so that in order for assignee to create approval request one must also have one of the selected project roles.
Who can manage approvals
Listed project roles will be granted permission to vote on behalf of approvers in issue.
Actor
Approval process allows automatic issue transitioning. This setting proposes selecting a person on behalf of whom this transition will be made.
Paste to comment
If activated, your comment in approval request not only will be sent as an e-mail, but also will be left as comment in issue.
Comment on vote
Enabling this checkbox makes a comment dialog window appear when approver uses Approve of Decline button in issue. By default this checkbox is disabled and leaving vote is usually instant and does not propose leaving a comment. However, when checkbox is enabled, administrator can make Approval or Decline decision to require a comment upon voting by checking the newly appeared boxes:
Comment on approval is required
Comment on decline is required
Automatic comments
This section contains 3 fields. In each of these fields project administrator can set a text message tat automatically will appear in issue as comment when request is complete. Corresponding comment message will appear depending on the final status of the approval.
Add approvers to field
As an additional feature, project administrator can choose a custom multiple select user picker field to populate it with users mentioned in approval request.
Create new configuration
To make approval process possible, project administrator must create configuration in project for a particular issue type.
Steps:
Select issue type
2. Configure statuses and transitions
You can choose statuses where approval functionality can be used. Approval requests can be created only when issue is in any of the chosen status. To add new status configuration press 
button.
Optionally some transitions in this status can be triggered automatically depending on the approval result.
3. Auto expire
To prevent long lasting unresolved approval requests, there is a functionality of auto expiration. If set up, approval request will be automatically cancelled if issue has no updates more than selected number of days.
After all configurations are made, press Save to keep the changes. Configurations can be deleted individually or all at once with the "Delete all" button.
Notification
On this tab project administrator can change default notification message for this project. And can make these messages be resent automatically based on a fixed schedule.
Default notification template
By default, all projects have the same notification template. It you want to change it, go to Manage apps → Issue approval → Configuration List → Notification. Once modified - all projects that have no own template shall use it.
Press the Edit button to modify template.
Apart from the text (supports wiki markup), administrator can use variables to fill template with dynamic data. Variables will be automatically replaced in email to the necessary value, like issue key, approver name, issue priority and many more.
To add variable to email template press button to call a drop down menu.
Using the search bar or just scrolling down, find the variable you are most interested in.
Clicking on it will paste this variable into the text area. You can add as many variables as you want from the list.
You can modify not only text in the template but also the header picture. Click Upload custom header image and select one.
Uploaded image must be under 200KB with resolution 600x140. Otherwise it will be adjusted to this resolution.
This picture will be used as a header image in emails sent to approvers.
Schedule
This option allows re-sending notifications to approvers according to a configured schedule. Below the Default notification template, project administrator may find a Schedule menu.
Single notification may occasionally be ignored or lost of sight. So scheduled reminder will make sure approver will not loose an important email.
Using a set of interrelated fiends administrator can set up time interval to send notifications to approvers.
Once a day, week, month or every X hours or minutes.
Requests
Lists all requests related to this project. The table shows both, waiting for completion and completed requests created in this project. Each issue can have several request records.
Use filter to find a particular request created in this project.
You can search for requests not only by issue keys (if known) but also filter them by status and/or creation dates.
Click expand to see more details of approvers' decision in this request.
Requests marked as yellow are not completed, but issue status does not allow to proceed approval process. To solve this problem, transition issue to the status that allows collecting approvals according to configuration for this issue type.
Requests marked as red, mean that there is no configuration for this request. You can either delete such requests with the Clear invalid requests button or make a configuration of issue type and status so you could proceed.
Button Clear invalid requests cancels all corrupted requests in project that have no configuration (red).