Hi Dyvia,
You can encapsulate both creating the record in first entity and updating value in the second in the single action. Pay attention that in this scenario, by default, both actions would be part of a single transaction meaning that if updating the second entity fails, the creating record in the first one is rollbacked.
If you are seeking for the updating of the second record to be something assynchronous and to run in the background, you can use a BPT:
Note that in this scenario, the trigger is on the database and that you would have to check the "Expose process events" option in the table where the trigger is.
Hope it helped.