How can I give the player an item from another mod?

This will be possible starting MCreator 2023.1 which adds procedures to get blocks and items from other mods by their registry name and also procedures to check if a mod is loaded

Waiting for 2023.1, you can use loot tables like I did with my mod here : menethiss-zombie-apocalypse-mod to put that into chest, gui or something else, or you can use commands.