When you become a limited company, you must display your company details on all your correspondence.
Typically, this will be:
– sales invoice
– letterhead
– email
– website
The company details will be:
Company name
Company number
Company registered office
Changing your email signature is very easy, changing letterheads is a bit trickier since you’ll have to get them re-printed. However, the reality is that fewer and fewer people send letters these days so as long as you can change a pdf letterhead you should find that this will cover most correspondence.