Funds to buy property can come from a variety of places, including:
Savings
Bonus from work
Inheritance
Business profits
Equity in your home
Equity in your property portfolio
Funds from other people, family, friends, colleagues
You can even invest pension funds, however, can only be invested into commercial property
My first house was bought with a 100% mortgage, meaning I did not have to put any money in myself. Later my funds were from equity, savings, and friends and family.
I have found buying a property using savings and equity can be slow, but combining funds with other people does speed things up.
If you do invest with other people, is essential to understand and be comfortable that you are in a financial relationship with that person for a long time.