Theresa May is a lady who used to be in charge of the United Kingdom. She was known as the Prime Minister. Just like how you might be the leader of a game with your friends, Theresa May was in charge of the whole country, which is kind of like a really big game.
She became Prime Minister in 2016 after the last leader stepped down, and she remained the leader until 2019. While she was in charge, she tried to do things like make the country safer, help people get better jobs, and make sure that everyone had a fair chance to succeed.
However, some people didn't always agree with the things she did or the way she did them. They had different ideas about what was right for the country, which sometimes caused arguments and disagreements. In the end, Theresa May decided to step down from her job as Prime Minister because she felt it was time for someone else to lead the country.
So, Theresa May was a lady who was once in charge of the United Kingdom, but she is no longer in that role now.