Photo by Olu Eletu at Unsplash.
This is a short one and quite easy. When you create an item in SharePoint the unique identifier for a person field is the claim, while the Get Manager action takes a UPN (user prinipcal name).
For Office 365 they are almost equal. The claim is actually the UPN + a claim prefix.
UPN: john@contoso.com
Claim: i:0#.f|membership|john@contoso.com
If you have a flow triggering on a SharePoint list, you would enter the following expression for the UPN field to strip off the prefix from the claim.
replace(triggerBody()?['Editor']?['Claims'],'i:0#.f|membership|','')
Sure you can use the e-mail address which usually match the UPN, but you would be surprised how often multiple accounts have the same e-mail address - admin accounts, test accounts etc. So using a unique identifier is always a better approach compared to the e-mail address.
