What is the difference between cover and coverage in English?

1) Meaning and Translation of "Cover" as a Noun

In the sentence describing mailing, the meaning is "one envelope, one mailing", which can be translated as "with a letter, by mail, letter Commonly used phrases are in one cover (attached to the letter, mailed with the letter); under separate cover (another letter mail or separate mail); under registered cover (registered mail, registered letter) and in a separate cover (another letter or another letter package). For example:

The negotiating bank should send all documents in one cover to our international division.

The negotiating bank should send all documents in one cover to our international trade department.

We are sending you under separate cover by airmail some sales promotional literatures.

We are sending you under separate cover by airmail some sales promotional literatures.

2) Coverage" is another derivative of "cover", as a noun, mainly used in insurance situations, the meaning of which is "insurance, insurance, insured", such as:

Risks & Coverage 險别

increasing coverage , extending coverage 加保

renewing coverage 续保

We can serve you with a broad range of

We can serve you with a broad range of coverage against all kinks of risks for sea transportation.