Both can produce silk
Ideally, both male and female spiders are eligible to build webs and create silk.
Females are the ones who usually create webs
Most of the time, female spiders build webs. It is acknowledged in arachnology literature males do not do web building; they are required for not other than sperm induction. At the same time, female spiders build astounding webs.
Adult males build webs very rarely
Only Juvenile male spiders build webs, that too till the time they are young. When they grow up, they stop making it.
Spiders seen in webs are usually female
Usually, female spiders live in the webs they build. (See Why do some people fear spiders?)
Females build more significant webs
Male webs do not often build webs. But even if they do build them, their webs are very less complex and straightforwards. Whereas, if you notice, webs made by female spiders are extraordinary big and quite complex.
Males build webs for mating
Male spiders build their webs only when they want to mate with a female spider. Male spiders pour their semen on the web made by them to attract and let female spiders know that they want to mate. (See How Testosterone affects male behaviour?)
Male spiders abandon webs
Once the male spider mated to a female spider, they abandon the web and start searching for the new web along with the partner, to mate with. That’s why usually female spiders are seen on the web, not the male.
Some males use female webs to eat
Some male spiders use the web created by a female spider to eat. Those spiders consume the prey caught by the female spider’s web.