SharePoint Enable users edit permission on items they created

Go to list settings and click on advance settings and search for Item-level Permissions, you will get the option to change the permissions for SharePoint list without any customization. Select Create and Edit items by the user option and save the settings.

Why we need this?

There are scenarios where organizations or IT teams need security customizations in list and libraries to allow users to modify or view their content only. Specifically in scenarios like they are submitting a leave request, expense request or submitting a ticket where do not need option to modify content submitted by other users or they can only view content they have submitted. Enabling unique permission for each item is not the required solution as lists are expected to be large in size with time.

So in such scenarios/requirements, the best possible solution I through modifying the list permission through list advance settings.

Change list settings using PowerShell

You can also change the list settings by using PowerShell, I am sharing a small PowerShell cmdlet to change the list item-level permission settings for the list. I am using PnP powershell module:

#connect to sharepoint online site
 Connect-PnPOnline -Url "https://mstalk.sharepoint.com" -Interactive

 #Name of List 
 $listName= "Issue Tracking" 

 #Fetching list
 $list = Get-PnPList $listName -Includes ReadSecurity

 #updating set list item-security to read items created by the user
 $list.ReadSecurity = 2
 #updating set list item-security to edit items created by the user
 $list.WriteSecurity = 2 
 $list.Update()