In addition to the answers above, I'd like to add:
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You might want to grant this to a **role** instead, and then assign the role to the user(s).
Suppose you have created a role `myAppRights` via
CREATE ROLE [myAppRights]
then you can give execute rights via
GRANT EXECUTE TO [myAppRights]
to that role.
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Or, if you want to do it **on schema level:**
GRANT EXECUTE ON SCHEMA ::dbo TO [myAppRights]
also works (in this example, the role `myAppRights` will have execute rights on all elements of schema `dbo` afterwards).
This way, you only have to do it once and can assign/revoke all related application rights easily to/from a user if you need to change that later on - especially useful if you want to create more complex access profiles.
**Note:** If you grant a role to a schema, that affects also elements you will have created later - this might be beneficial or not depending on the design you intended, so keep that in mind.