Format Of Confirmation Letter With A Unique Touch

Dear Citehr members,
I am working for organisation which is running from last 10 years. It hasn't given formal appointment letter to its employees.. since it is expanding and growing.. looking to setup systematic HR system...
is there a format which can fill the gap of appointment letter along with confirming their service..or a mix of appointment +confirmation+extension of their service..
plz help
thankyou

I also have the similar requirement of an 'all in one' letter for the old employees. Seniors please help.
One more concern is that as I am giving appointment letters to new joinees but my old employees feel demotivated bcoz of that, so how to handle that situation?
I believe the only option is to give a formal letter (appointment +confirmation+extension of their service) to them.
waiting for replies...
Regards,
Gunjan Malviya