How to set up api access to be able to access from outside?

Question

go

When trying to access APIs deployed on Heroku, the request is blocked with the following message
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ..... (Reason: CORS header 'Access-Control-Allow-Origin' missing) .[Learn More]
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ..... (Reason: CORS request did not succeed)
. from the outside front?