In what situations can I use letters after your name?

geek84

Good Morning Folks

I am in the process of applying for jobs at the moment. I have book keeping and accountancy qualifications. Could someone be kind enough to tell me in what situations I can use the letters associated with the relevant qualifications after my name? Can I or do I use them most of the time? When just completing an application form (non job related), can I or should I use it then?

Any advice greatly appreciated