There is always more to be said, but you and the readers here may be interested in two of my previous answers:

Were women’s pockets made small after the French Revolution to prevent assassinations? (No.)

When did pockets in clothes become common?

To quote from the latter:

For women's clothing, the story is different. Where men began to wear integral pockets sewn into their clothing in the 16th century, women began to wear something a bit different. Flat, lightweight bags with a slit in the front were attached to woven tapes and tied around the waist underneath the top petticoat (this is sounding pretty weird, so here is an example of a pair of pockets from the late 18th century as a visual aid), accessible through slits in said petticoat. These were sizeable - it's not always clear just from looking at an image like the previous, but a perfectly normal pocket shown in Janet Arnold's Patterns of Fashion is about 16" deep and 10" wide - and were worn until the change to a narrow Neoclassical silhouette at the very end of the 18th century. The stereotypical Regency dress did not allow for a large pocket full of items: that would create a nasty bulge under the skirt. So the pocket moved outside, to be carried in the hand as a reticule. (By the fashionable. Some women continued to wear utilitarian pockets under their gowns.)

Pockets did not return to their hidden place until the mid-19th century, when the skirt became full again. These pockets were usually set in on only one side of the skirt, and made of a plain cotton with a facing of the skirt fabric around the opening. Again, when fashion decreed that the skirt be cut close to the hips after the turn of the next century, pockets became less common again except in looser sporting clothes. This pattern of pockets becoming common or unlikely as the fashionable skirt shape became full or tight would continue over the 20th century as well; a similar deal went on with women's trousers.