How to call a phone number on a picture?
This feature isn’t implemented in iOS. You would probably be fastest to ask Siri to dial the number via dictation if you can see the number and speak it.

Some third party apps have image recognition like iOS does in the notes app when you hand write things or when a PDF can be scanned into searchable / copy able text.

One third party app that has a scanner is Excel - you can take a picture of a paper table and it tries to automate the numbers and text that created the printed table.