A list of items of business to be considered at a meeting. It is a Formal document and is aimed at an audience that can be attending a meeting for example in a school the teachers can get the agenda to tell them what will be discussed in the meeting. One of the things that can be on the agenda is staff holidays and the date and time of the next meeting.
A list of goods shipped or sent, or services rendered, with prices and charges or even a bill.
Invoice is a Formal document from companies a receipt of your purchase it is aimed at the consumers which are customers who receive the invoice as proof of purchase. Some of the things that can be on the invoice are your address and the things you have purchased.
An informal printed report issued periodically to the members of a business, organization or a company. It can be used in the business to give the customers a newsletter about the company or business. One of the things that can be on the newsletter is the new things the company is doing or any special offers the company is offering.
The careful recording of a meeting, i.e. the writing of minutes, is an essential part of a meeting though it involves time and expense even after the meeting has ended. This is an informal document. One of the things that might be in the minutes are matters arising and date and time of next meeting.
Memos are a formal documents, you generally send memos to co-workers and colleagues; you do not have to include a formal salutation or closing remark. On of the things you might find in the memo is who it is from and who else has the memo been sent to.
A letter can be formal and informal it all depends on to whom you are writing to for example if you are writing to a company or bank then it must be formal however if you are writing to a friend or a colleague then it can be informal and brief. Some of the things you might find in the letter are whom it is sent by and...