There are several highly recommended books for people getting started with PowerShell.
Learn Windows PowerShell in a Month of Lunches is a great getting started resource that introduces gradually into PowerShell scripting and the PowerShell environment.
Windows PowerShell in Action was authored by one of the language designers from Microsoft. It provides a very deep level look at all the features of PowerShell. Although it’s focused on Windows PowerShell, the topics discussed still apply to PowerShell 7.
Windows PowerShell Cookbook is authored by one of the software developers at Microsoft. It contains around 100 different recipes.