How many times is apple allowed to charge your card for payment of a subscription

In my experience, Apple will try to roll up multiple iTunes or App Store purchases onto a single bill. If you buy a song – then don't buy anything else for a while – there may be a little delay between the time you purchase the song, and the time they charge your card, while they wait to see if you are going to buy some more small stuff.

On the other hand, with Apple Music and iCloud+, they send bills for those separately. (I'm not on an Apple One subscription plan where those things are bundled together.). The bills may come at different times of the month.

The number or spacing of bills, per se, should not be a problem as long as the bills are correct. If they saved everything until they could send out a single monthly bill for all of your subscriptions and purchases, you'd still be paying the same total amount.

I don't quite understand your question? If you subscribe to something through Apple you'll be charged per the terms and conditions of what you bought. That can be a monthly charge or an annual subscription charge.

Other than that, without more details about your purchase, we can't offer much more guidance.