iCloud storage

iCloud storage does not add more storage to the phone. The phone has a fixed amount of storage when you buy it and that cannot be changed.

Take a look at this.

What's the difference between device storage and iCloud storage? - Apple Support

You need to delete content on the phone to free up space.

How to check the storage on your iPhone and iPad - Apple Support

Manage your photo and video storage - Apple Support

I bought 50gb iCloud storage & paid 75₹ via phone pay but the storage is still not reflecting in my account

If you have upgraded iCloud+ plan, once your request for iCloud+ plan has been activated, you should receive an invoice in your email box.

Please check -> Go to -> Settings -> your name -> iCloud -> if you see 50 GB (or 200 GB or 2 TB) then you have an iCloud subscription.

If you have an iCloud subscription, you will receive a monthly bill from Apple, check your email box.