Q: Is their a way to buy apps using your Giftcard without entering your credit card info

Yes you can use iTunes gift card(s).

Create an iTunes Store, App Store, or iBooks Store account without a credit card or other payment method - Apple Suppor…

OK, then you must have an Apple ID already set up with a credit balance.

You can check this on your iPhone by going to Settings > iTunes & App Stores > View Apple ID > [Sign in} > [scroll to the very top] Apple ID Balance.

You cannot use this gift card balance for certain purchases; e.g., buying a gift app for someone else.

OK, that sounds fine!

You started by asking about your gift card.  I told you how to learn about your gift card information.

Then you said you do not wish to enter your credit card information.  I told you how to set up an account without entering it.  You said you already have an account.  I told you how to see your gift card balance.  You said "My credit card info is not there."  Of course it is not there!  You never entered it!