@here Does someone know what is the significance of Revenue arrangement?

it is a transaction that ties in all revenue elements, revenue plans, calculates fair value, etc.

Thanks is it required while charging customer?

It is designed to be a transaction that ties in for revenue recognition - that is why your question would be better asked in the ARM channel (advanced revenue management)

Can you add me in ARM channel (advanced revenue management)?

you can search for it by clicking on "channels" in the left hand pannel and searching for "arm"

Thanks