SparkFun Electronics has great tutorials on electrical theory and tutorials on electronics and Arduinos.
https://learn.sparkfun.com/tutorials/what-is-electricity#getting-started
For more information and visualizations explaining electricity, visit https://www.saveonenergy.com/how-electricity-works/
Here are some other beginner level concept tutorials we'd recommend reading through:
Or, maybe you'd like to learn something practical? In that case, check out some of these basic level skill tutorials:
Use this tutorial to learn the absolute basics of using Tinkercad Circuit Diagrams