Hello! Technically this sentence means that tomorrow is the day you want to make the appointment, not for the appointment to take place. However, since it makes no sense (no one calls to say: I'm just calling to let you know that I'll be calling again tomorrow to make an appointment), we understand that it is FOR tomorrow. But let's see what actual natives have to say about this...

Hello, Helene is correct. It would sound better to say: "I'd like to make/book/schedule an appointment for tomorrow." A native speaker would still most likely understand what you mean with or without the "for". Take care.

In American English, prepositions are sometimes left out, especially when they relate to time. In casual American English, it's common to hear sentences like these: ~ The meeting is Friday (rather than the meeting is on Friday). ~ I booked a lesson tomorrow (instead of I booked a lesson for tomorrow). These sentences can sound a little weird to speakers of British English and to English learners.