The invisible finish, also known as the invisible fasten off, is a crochet technique used to complete a project. It's called "invisible" because, when done correctly, the fasten off point blends seamlessly with the rest of your stitches, making it difficult to discern where your project ended.
Complete the final stitch of your project as you normally would. Cut the yarn, leaving a tail about six inches long.
Once the yarn is cut, you should still have one loop on your crochet hook. Pull the end of the yarn through this loop. Be careful not to tighten this too much.
Thread the tail of the yarn through a yarn needle.
Insert the needle under both loops of the second stitch following the final stitch of your project (from front to back). Pull the yarn through. (Some like to use the very next stitch instead of the second, but this will create an extra "V" along the edge, so we don<t recommend it).
Pull on your tail just enough for you tail to create the front loop of a sticth, betwen the last stitch if the round and the sticth you just went under
Now, insert the needle back through the middle of the last stitch of your round (where your yarn originally came from), going towards the back. Pull it through carefully to finish the illusion of a regular stitch.
After you've completed these steps, the end of your yarn should now be at the back of your work. You can then weave in the tail of your yarn into the back of several stitches to secure it and ensure your work doesn't unravel.