How do I exchange currency

So I live in the UK specifically   Scotland and I want to get a subscription and when I looked for more currencies I couldn't find any other currency but how could I exchange GBP to USD. Thanks for reading.

Should be zero problems as your bank will just do the conversion; the only thing is that while you can search actual exchange rates, that won't account for any fees from your bank (or Paypal).  

Inefficient said: So I live in the UK specifically   Scotland and I want to get a subscription and when I looked for more currencies I couldn't find any other currency but how could I exchange GBP to USD. Thanks for reading. I am in the UK also and I have had no issues in 7 years.  There is a conversion rate and then the bank charges around 20p  as a transaction fee. 

Another UK user, and I just use my credit card and it accepts the payments being made in dollars and just converts it for me.