Hello, tell me, is it possible to make it so that the item shows that it is for a quest, although this quest has not been taken at the moment, but can be taken in the future?

its.. complicated.. all the things addon can show quest items.. we can show quest items and by that i mean items tagged as Quest (normally quest starters) but i presume you are asking about item x being needs for cooking quest y that you dont have yet?

if not clarification needed

Yes, there are no quests yet, but the item is knocked out, and it may be useful in the future for a quest, and you sell it to the vendor, unaware of this

there were a few addons that did this (show in tooltip item used for blaat) but the problem is it takes a DB of quests and items, which isnt in the classic API yet.. retail API has a complete set of server pulled info from in game for recipes and reagents for same..

so, much as i personally would love it, i dont see it happening in Questie at this time.. feel free to tag this as a feature request and we can keep it in mind for the down time (yeah, i sniggered while writing this)