need help setting up iphone

lwclic wrote:

My husband and I share this account.

Share what account?

• The gmail account? Add it as a Google account automatically using this method. Add an email account to your iPhone, iPad, or iPod touch - Apple Support
• Your Apple ID? Stop doing that immediately! It causes nothing but problems. Each unique person needs her/his own Apple ID.

Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support

I bought a new I-phone SE today and they transferred Apps etc at the store, but when I got home I cannot get my gmail. The account was originally set up as a harter.net account, but I no longer use it. I use gmail. The phone will not let me add the gmail account. It says this address is not available. My husband and I share this account. I have never had this problem when purchasing othe i-phones.