Hi @harpal rana ,
We can grant access using SharePoint App-Only. Please set permission with list like following
<AppPermissionRequests AllowAppOnlyPolicy="true">
<AppPermissionRequest Scope="http://sharepoint/content/sitecollection/web/list" Right="FullControl" />
</AppPermissionRequests>
Then use client id and client secret to access sharepoint online
Please refer to the following link to grant access
https://learn.microsoft.com/en-us/sharepoint/dev/solution-guidance/security-apponly-azureacs
following link for permission level
https://learn.microsoft.com/en-us/sharepoint/dev/sp-add-ins/add-in-permissions-in-sharepoint