Is the commission paid by the company for collecting and transferring funds to local clients permissible or forbidden (halal or haram)? And is it permissible to raise the transfer fee for clients?

We understand from the question that the company has authorized you to deal with its customers by transferring the amounts with which they will purchase, in exchange for a known commission for each amount transferred. There is no harm in this. Similarly, your exchange transactions with the company's customers (money exchange) are also permissible if the exchange takes place on the spot at the time of the contract between you and them.

As for the daily rate, you are not obligated to adhere to it. Rather, you may ask for an increase over it as long as the currencies are different, such as dollars for dinars and so on, according to the saying of the Prophet, peace and blessings be upon him: "If these types [of currencies] differ, then sell however you wish, if it is hand to hand." The increase is for your company, not for you. Then know that possession in the contracting session is a condition for exchange. Possession is of two types: actual possession, which is the physical receipt and delivery of both currencies by hand, and the second type is constructive possession, which includes certified checks and ledger entries. If this is present in your transactions, then there is no objection.