What's "put in" mean?

Native speaker’s answer
Rebecca
To "put in" in this context means to devote time, effort, or resources to do something. In this case, the speaker says "put in the time and effort" to mean "devote the time and effort." You will often see the expression used together with "time and effort" Ex: I put in a lot of time and effort to succeed at school. Ex: I put a lot of my personal savings into this business.