There are lots of ways to get seeds. Sometimes you find seeds in some marijuana you buy. Just pick the seeds out of the marijuana and you’re set. Unfortunately, most weed these days comes without seeds. In fact, it’s been that way so long that it’s not even called “sin semilla”, which was what we called it in the old days before growing only females was common .
You can buy seeds, of course. In some jurisdictions it’s legal to sell them openly. You can also buy them from magazines or over the internet. The advantage to doing it this way is that you have a wider variety of choice. However, it may be illegal, so check your local laws.
However you do it, you end up with some marijuana seeds.
Different types of marijuana produce different seeds. Some are big and fat. They can also be tiny. Some are dark. They can be light colored. Some have dots. They can have irregular patches of light and dark.
What you need are healthy seeds. The shells should be hard.
If they are soft and green they’re too young.
Get an idea of how marijuana is growing.
Learn the tips how do you grow marijuana.