When it comes to printing on fabric, it can be difficult to distinguish what the best method of printing is for your garment, what the difference is between different kinds of prints, etc. So let's break it down.
Digital printing can be used for both wovens and knits. Digital printing is the process of printing intricate designs onto a garment or fabric. However, it's much easier to print at the fabric level vs the garment level. After a client provides the design files, it gets printed onto the fabric or garment as specified. In the ideal case, fabric is printed in bulk rolls by a large digital printer. In specialized cases, the fabric is printed after being cut. This is done when there is a pattern or design that extends beyond the seams of the garment.
There is a high failure and waste rate when digital printing is done at the garment level as you have to match the pattern across fabric seams. Digital printing is a good solution for lower volume production, however it doesn't scale up efficiently so it can be impractical for high volume orders.
Gel printing can be done on both wovens and knits. Gel printing is the process of designs being printed via a gel ink that creates a high profile print that feels like rubber or silicone. After a design file has been provided, the gel printer lays a layer of gel on the garment. Once dry, the gel adheres to the fabric. Long term, however, the gel can come off of the fabric. Gel printing is particularly great for streetwear and athletic wear.
The one caveat of gel printing is that it does not work well on coated fabrics, including waterproof or resistant coatings.