Barclays is one of the largest UK banks, offering the full suite of financial services products.
You can open a current account, savings account or take out a loan with Barclays. You can't get a credit card directly through Barclays, but its sister brand Barclaycard can provide one.
Barclays offers mortgages too, under The Woolwich brand, which it bought in 2006. While it does still use 'The Woolwich' as a trading name for this part of its business, in practice you're getting a mortgage from Barclays.
It also offers a range of insurance products but Barclays itself is not an insurer. Its policies are underwritten by various other insurers, depending on the type of insurance.
Home insurance is provided by Gresham Insurance Company, and travel insurance by CIGNA.
Barclays life insurance is underwritten by Aviva, unless you are getting a deal as an existing mortgage holder, in which case Legal & General will underwrite the policy.