In Spanish, you say ‘I will return’ as ‘Volveré’.
This phrase comes from the verb ‘volver’, which means ‘to return’ or ‘to come back’. The ending ‘-é’ indicates that it is in the future tense, so it clearly communicates that the action will happen later. For example, if you are letting someone know that you will come back to a place after a while, you might say, ‘Volveré más tarde’, which translates to ‘I will return later.’