A fraction of a share is a portion of a full share of a company or ETF. Fractional investing allows you to buy portions of shares instead of purchasing an entire share. With fractional shares, you can invest as little as you like, regardless of the price of one share. You will still receive dividends based on the portion of the share you own, but you have no voting rights.
As with any investment, you need to consider the fees before investing small amounts to make sure it’s worth your while.