There are 2 ways to lend Bitcoin.
1. Lend on forums like Bitcointalk directly to individuals. The return is bigger, also the risk. You need collateral, you need escrow, you need some knowledge.
2. Lend on websites, which will do the job for you, but the income is smaller. The one I've trusted for this was Poloniex (yes, a few exchanges do have lending), but I withdrew my funds from them about 7 months ago. There's a risk there too, but way smaller.