Inventorio mod maker says that there is a button in the upper right corner of the inventory in your mod and that we can access the trinkets slots by switching to the vanilla inventory with this button, but I did not see such a button.

shouldnt you ask inventorio about that?

I asked her too but did not get a clear answer.

uuh

you mean the button in the top right from the screenshot (in the description) here
https://www.curseforge.com/minecraft/mc-mods/inventorio

that'd be a button from the mod inventorio

yes and that button is not visible