used for saying that something is enough or is appropriate for a particular purposeIf you don’t have a proper bandage, any strip of clean cotton or linen will do.
“I suppose we ought to tip the waiter, but I’ve only got 20 francs left.” “That’ll do.”
will do as/for (=be suitable to be used as something): An empty box will do for a table.
will do someone (=will be good enough for someone): “All I’ve got to offer you is instant coffee.” “That’ll do me just fine.”