How do I adopt children on the Sims free play

The only alternative is to adopt - but that costs real-world money ($4.99 per kid!). You do the math and decide for yourself.

On the other hand you could just farm LP?

There is no such thing as “Free LP” - the closest thing you can get to that is to pick two of the easier hobbies to master - Ghost Hunting and Diving are our go-to choices for this - and then have four Sims doing each Hobby.

Once you master the Hobby collection the reward Changes to LP - 5LP for Ghost Hunting and 3LP for Diving being the examples. You can very easily generate significant amounts of LP using that method daily.

Unfortunately their is no other way of getting a baby as far as I am aware however, a good way of getting LPs is you can leave your Sims alone for a little while, a week or so, maybe a bit longer, just don't visit them a bit so that they become 'housebound', then when you return to the game it should give you some LPs to 'get your Sims' mood up' but you can just use it for something else I.e having a baby.

A way to adopt in Sims Freeplay without spending money is to have a child’s parent(s) killed off, then have that same child build a relationship with the Sim(s) you want to adopt the child. Once they’ve become best friends, you’ll get the option to adopt the child.

If you want the romance interaction to be available you need to complete the two main tasks once your level 7