To custom bot name and icon:

Step 1: Log in to JIRA Server as an administrator

Step 2:

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Choose Settings button at top right corner Image Added

Step 3:

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At drop down menu, select System

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Step 4: At the left hand side, scroll down until

Slack Integration

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option > choose App setting

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Step 5:

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Input Bot Name and copy image url to Bot Icon

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Step 6:

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Step 7: Modify message then click on Send Test to view the result which is already sent to configured channel

Create a JIRA ticket:

Step 1: Log in to JIRA Server

Step 2: Click on Image Removed on the top menu 

Step 3: Create a JIRA ticket

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Step 4: Open Slack channel 

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Click on Image Addedbutton

Create an Jira issue and log in Slack to view the changes