The Finances section in the game shows you all your expenses and income in the game. Your sources of income are as follows:

Awards Prizes:

This is a cash reward that you receive after your matches. Rewards for league matches are constant throughout the season, however they increase/decrease from one level to the next.
The Cup reward depends on the stages of the competition. The more you advance in competitions, the more your income increases.
Higher level managers receive more income from competitions compared to lower level managers.

Ticket selling:

Ticket sales are a means of income that depend on attendance at your matches. Upgrade your facilities and optimize ticket prices according to your level and match importance to increase your ticket income.

Other sources of income:

These include transfers, manager sponsorship, betting rewards and sponsors. Please note that optimal management of your team will allow you to diversify your sources of income and increase your funds.