This word is widely used when refering to the future. The construction is:

majd + present tense

Do not use future tense with majd. Such a form doesn’t exist.

It is used when I promise I’ll do something or I offer something I’d do with pleasure. It has a more casual and friendly tone to it then the paraphrased future tense.

Paraphrased: Meg fogom csinálni.
Majd: Majd megcsinálom.

The paraphrased sentence means: I’m definitely going to do it. The majd sentence means: I’ll do it (sometime).

More examples:

-Kitakarítottad a szobát? – Did you tidy up the room?
–Majd kitakarítom. – I‘ll tidy up later.
-Inkább majd én! – I‘ll do it!

But it also has a derogatory shade sometimes:

A leckédet meg majd én írom meg helyetted, nem?
And I’m doing your homework for you, right?

That’s all about future tense. Bye 🙂