Insert a People Picker in Canvas Power App using Combo Box. Below are the steps:

• Add Office 365 Users Data Source.

• Add a Combo Box. Click on Edit Fields on Properties Bar.

• Select Person as the Layout.

• To pre-populate the Combo Box with the existing value, write below code in DefaultSelectedItems property. RequestSubmittedByEmail and RequestSubmittedByName are the names of columns in Table

{
'@odata.type': "#Microsoft.Azure.Connectors.SharePoint.SPListExpandedUser",
DisplayName:ThisItem.RequestSubmittedByName,
Claims:"i:0#.f|membership|" & Lower(ThisItem.RequestSubmittedByEmail),
Department:"",
Email:ThisItem.RequestSubmittedByEmail,
JobTitle:"",
Picture:""
}

• Set Items property as

Office365Users.SearchUser({searchTerm:cmbRequestSubmittedBy.SearchText, top:10})

cmbRequestSubmittedBy is the name of the Combo Box

• Set IsSearchable as true
• Set SearchFields is [“Mail”] as we will be searching using Mail ID.
• Set InputTextPlaceholder as “Enter Email ID”