If you don’t know how to select all messages in gmail after filtering your email list then follow these steps:-
1. The first step is to go to your inbox and conduct a search or choose a specific label or category in Gmail.
2. Then click on the drop-down menu which is next to the main inbox.
3. Now choose any option from the menu.
4. Then select all conversations in the Primary option to select multiple emails all at once in the primary inbox.
5. Now finally you can apply any option.
