but seeing more of the increase in the number of users who are engaged in using Bitcoin for different purposes, why the indication of increasing rate in Bitcoin transaction is very important and more considerable on this regard.
You never can know how many people are using bitcoins, it's an impossible task because with Bitcoin blockchain, it's public and everyone can check blocks, addresses, transactions but they can not know who are owners of those Bitcoin addresses.
Professional on chain sites only can give you information like active Bitcoin addresses, but they can not show you the number of active Bitcoin users or total Bitcoin users.
https://www.lookintobitcoin.com/charts/bitcoin-active-addresses/