In Power Automate if you enter the dynamic content value from a lookup column typically you just get the GUID or if you select the dynamic value of a choice column you just get the ID number for that item.
THIS CAN ONLY WORK ON OUTPUT FROM A GET ACTION OR LIST ACTION!
Here is an example expression you can use to get the display name instead:
@OData.Community.Display.V1.FormattedValue is the important part that can be added after the _value.
Here is how I build this out for my flows using Modify By as an example
Create a compose action and select Modified By (Value) as the dynamic content
Click the … and select peek code
I then copy AFTER the @ symbol and stop at the last double quote like so:
I then paste into notepad and add @OData.Community.Display.V1.FormattedValue after value:
Copy what you have created and it in the expressions section and click OK and you are done: