CAD
Cloud based cad software
To be completely honest, very few cloud-based solutions are industry standard. Most companies will not trust their documentation to a could service and pay a subscription to access their engineered content. That being said, it is much easier at the middle and high school level to learn cad software with a cloud-based solution because a weaker computer without a great graphics processor can run those cad solutions.
The two most common cad solutions for schools are Onshape and Fusion 360, because they both offer free for personal use solutions. In each case, you will need to create an account to use the free software.
Tinkercad
Tinkercad is a great place to start learning about cad software. Some of the concepts translate to other 3d programs and it is completely free. You could make individual 3d printed parts easily with Tinkercad, however it does lack some of the tools that other CAD software offers when it comes to making a complete assembly.
Tinkercad does require an Autodesk account. You can use the same account for Fusion 360 if you decide to start with Tinkercad and 'graduate' to CAD software with more features.
Onshape
Onshape is incredibly popular in Middle and High School Robotics programs and fairly easy to use. It is entirely browser-based so you don't need a high-end computer to operate it. An account is required.
You aren't likely to see any companies using onshape professionally, but it is a great tool if you want to create personal projects and work on CAD in school.
https://www.onshape.com/en/products/free
Tutorials
Beginning Onshape (4 years old)
Fusion 360
Fusion 360 is popular for manufacturing and is not terribly difficult. It is typically provided as a download and does require a decent graphics card. There is an online version of the software, but it requires a school to register accounts for the students and get them set up.
You don't need any subscription to make basic parts and assemblies. This is a great program for making 3d printed parts. You can use this offline, but every two weeks you need to connect for it to re-authorize usage. There are a lot of really great tutorials for Fusion 360.
https://www.autodesk.com/products/fusion-360/personal