You are now one of the random forces that isekais people.
When you isekai someone they are sent from their current world to another of your choice.
You must give the individual a boon of some kind and a task they can reasonably accomplish in the new world using means available to them in that world (including using your boon).
The boon given must be a power or skill you yourself possess. As such, it is recommended you have some other power beyond this one. Don't worry, you don't lose the power/skill/etc that you give them, they simply receive a copy of it.
You do not need to let the individual know what the task you gave them is, though be warned this reduces the likelihood they will accomplish it.
Once their task is complete they are given the option of returning home or staying in the new world. Regardless of their choice, they keep the boon granted to them.
In return, after they accomplish their task, you gain all the experience the individual learned in that universe up to that point; all the magicks they mastered, the skills they learned, the science and technology they researched, etc. This also includes any interesting tricks they learned with the boon you gave them.
Should they die in the new world, you do not gain the experience and the isekaied individual is teleported right back to the world they came from with no time having passed and no memory of having gone. Yes, this means you can isekai the same person over and over with a different boon each time until they succeed.
When you isekai someone, you can choose to speak to them directly prior to insertion. Such a discussion will happen in a pocket dimension of your own design and no time in either world will pass during these talks. You can also choose to simply send them with only a vague or instinctive knowledge of the boon and/or task given to them (you may choose only one if you wish), or instead with no knowledge of either.