It is a good practice to embroider without knots! There are many ways to start or finish a knotless cross stitch. This method is very simple - its main advantage is that the fastening is done from the front. If you are embroidering on a machine or large hoop, I strongly advise you to try this option.
The thread that goes under the crosses is not visible at all and therefore the embroidery looks neat and beautiful!
This example was made on Aida 14 canvas. If you take Aida 16 (i.e. a smaller canvas in terms of crosses), the crosses will be more dense and the tail of the thread will not be visible at all!