i cant download free apps in my i pad ,any help?

If you can't make purchases or update apps, including free apps, you need to update your payment method or add a new one. 

Or 👉 Sign in to your Apple ID account page and edit your Apple ID details.

https://appleid.apple.com

On the Sidebar click Payment methods -> then tap Payments Methods and tap Manage payment method.

Or use another payment method: Add money to your Apple ID balance

Add money to your Apple Account balance - Apple Support (IN)

See also -> Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK)

See the Apple Support article(s) below. 

Apps won’t downloaded.  *

ASC YouTube for what to do if you can’t make a purchase on your iPhone -

App Store, iTunes Store, or other Apple services - If you can't connect   *

Some things you can try. Do you have access to another WiFi network where you can try? That has worked for several people.

Try a restart.

Restart your iPhone, iPad, or iPod touch    *

Try a forced restart. See the section towards the end of the article.

Reset Device. -

If necessary

Hard reset.     -

Do a backup and try a factory reset. Then restore from the backup.

Restore to Factory setting.      *

Restore - If you see an error when you update or restore your iPhone, iPad, or iPod.   *

Backup - Restore your device from an iCloud or iTunes backup.     *