Mend a dropped hem, duplicating the serger’s overlock stitch.
Mend a dropped hem, using a blind stitch.
To repair an opened seam, use a ladder stitch.
Mending hacks to repair a tear or hole in fabric.
Darn a hole in a knit fabric. This is an easy hack to fix a hole in socks.
This is the book I use for reference, picked up from the discard sale at the library years ago. It contains invaluable instructions for mending both knit and woven fabrics, and holes, rips, and seams.