If you are completely new to 3d modeling, you might want to try TinkerCAD as a simple browser-based modeling platform. That’s what I started with back in the day. My current preference is Meshmixer, a great tool by Autodesk with good functionality. I would advise you to look for full reviews to pick up software by different parameters - free\paid, browser-based\or not, for beginners\advanced users, etc (like all3dp review or artec3d review)
This may be a bit of a late answer, but it may be helpful to others.
Can you actually design anything in Meshmixer? I thought it was just for tidying up processed 3D mesh files?
Striiiiiiictly, it appears: Edit > Align To Target
Interesting use of meshmixer by a dentist here: Using Meshmixer to Open or Close VDO - YouTube I edit meshes in Fusion 360 usually these days since they made it onto the timeline.