What should the number look like if your texting a number in Sheffield or Leeds?

I have a friend in the UK.. I'm in the US... and he told me to use this to text him 0044 751 XXX XXXX! Is this correct.. or do I have to use 011 for the IDD prefix along with the 44 country code and the 114 for the area code and then his 10 digit number? So then it would look like this 011 44 114 751 XXX XXXX? Or how does it all work.. I'm soo confused... he was able to text my number with the 00 1 XXX XXX XXXX.. and i can receive the texts.. but I can't text him back... Help me please!

Ok.. just to clarify.. this is not to CALL.. it is to text him... I did call my cell phone provider to enable international calling.. but what I want to do is to text him.. like I said.. I can recieve his texts.. I just doesn't receive mine!!

Dial 011 (USA INTERNATIONAL DIALING CODE)
Dial 44 (to call Uk)
Then his number omitting the first 0

So call 011 44 751 xxx xxxx

Easy calculator on this link

00 is the UK access for international dialling.
you need to input your international access no, followed by 44 (for UK) and his phone number
0114 is the area code for Sheffield, however mobile (which you would call cell) phones in UK do not have area codes and all numbers start (0) 7, the 0 is omitted in international calls.
I hope this helps u

Ken B has it.
07XXXXXXXXX are mobile/cell number here so you don't need an area code. Form abroad this is 447XXXXXXXXX (drop the leading 0 as Ken B said).
If your international access code is 00 then prefix the country code (44) with that. However, on mobiles you can also use the + instead which translates to whatever the international dialing prefix is in the country you are in. This means you should be able to use +44 751 XXX XXXX from anywhere in the world you get a signal.. You get the + on some phones by holding down the 0 key for several seconds.

I call Leeds on 011-44-11-32-XXXXXX.
remember no zero after the "44" in the area code when dialing into the British phone system.

000000000000000

000000000