This answer is from my husband:

“Get an instrument; learn how to play it. Spend hours learning how to make your fingers make the notes happen. Learn how the songs you like are played, how the songs are composed. Find patterns that you like, and ones that you don’t. If you are expecting your computer to write the music for you, you cannot call yourself a musician.”

Knowing a bit of music theory helps. If you are new to songwriting, Google the circle of fifths.

Also, learning other songs (all parts) will help.

As one who has spent 60 years doing exactly that, I would second what @Seek says above.

My ex did this with downloaded software but he had it hooked up to a keyboard and also played the guitar and bass guitar. He had years of music lessons in school and read a book on music theory when he was trying to get into the local conservatory. He passed the theory exam with flying colours but didn’t play any instruments well enough to be accepted.
He was quite good and made some nice pieces of music. One of which was published on a compilation album.
Music theory is a must for composition. Years of guitar or piano. No short cuts.

Once you get yourself up to speed with an instrument or two, listen to some music you would ordinarily never listen to. It is difficult to be inspired by what we already like. Take what you dislike, or do not know, listen intently, then tweak away.
If you are just wanting to mess around, and not take yourself very seriously, you do still need to have some instrumental knowledge. Remember those awful flutes from elementary school? Give that a shot.
If you really want to go somewhere with this, then you must put yourself to it.

From the soul.

As @Here2_4 said, Once you get yourself up to speed with an instrument or two, listen to some music you would ordinarily never listen to.

This is similar to advice I give to students on a regular basis. I encourage anyone who wants to create or perform music to listen and learn styles and genres to which a person would not usually be exposed. There is much to be learned by expanding your listening repertoire, and you might even find something new that you like.

Here’s another suggestion for an instrument which might be easier to deal with.

You still have to spend some time mastering it but if you have short fingers like I do, this helps a lot.

Get an Autoharp. It’s a respectable musical instrument not a toy. Folk musicians use it all the time.

I wanted so badly to learn how to play a guitar and I did. But I was constantly having to transpose to a key with chords my fingers could form. (Theres a reason why someone like James Taylor is such an excellent guitar player. He has those elegantly long fingers and large hand span so can play the most difficult spread out chords with ease. His fingers are at least double the length of mine.)

Anyhow, an Autoharp has a number of bars across it with felt pads organized to press down different strings for the chords. Instead of trying to stretch or cramp your fingers in all sorts of painful contortions, it does the pressing for you.

You’ll still need to practice to get fluent with it but it’s not nearly as difficult as pressing down guitar strings. I think you’ll find it really enjoyable.

Don’t forget to buy a circular pitch pipe for tuning because new Autoharps need a while before their strings settle in.

But they’re steel strings so, once tempered, they hold their pitch pretty well.

Once you get familiar with your Autoharp, you can concentrate on making the kind of music you want.