Investments are great, but there are things you should know 100% about:
The contract with the investor must first of all describe the form of investment of funds. Yes, yes, there may be options! Option one is to invest directly. In this case, the investor becomes a shareholder/co-founder of the company, depending on the form of ownership (joint stock company or limited liability company). In this case, he's on an equal footing with the other participants in the project in proportion to his share or profits, or losses from business.
The second option of investing funds in a business project is to lend them to partners, which mean to conclude a loan agreement with them. If the loan was granted without specifying a specific term, the borrower is obliged to repay the debt within 30 days starting from the day when the lender claimed the debt.
In general, this method of capital investment is safer for the investor than participation in the business as a co-founder. After all, in this case the entrepreneur undertakes to return the invested funds regardless of how his business develops.
There is another way to invest - to buy the property itself (equipment, car or real estate) and simply rent it out to the entrepreneur. In this case, the risks of investment are minimal at all (unless the lease payments are delayed), but you'll have to bear the costs of repair and insurance, as well as pay tax.