I am a Registered Architect in the US, for the past 30 years.
Of course, the only acceptable program for architectural professionals is AutoCAD.
Currently, AutoCAD, is only made for MS/Windows or Apple/Mac.
I converted to Linux, over 2 years ago, and use GNU/Linux and Open Source exclusively.
For my architectural drawings I use either QCad or Archimedes for Linux. My 3-D renderings are done with Blender.
Both are very good and stable programs, though lack the maturity of AutoCAD.
A redeeming value of QCad and Archimedes is that they both save their files in the same format as AutoCAD.
So I can make and save my architectural drawings/rendering, in a CAD program for Linux, and open them for viewing and editing on a Windows computer.
Of course, there are other 'good' architectural/drafting applications for Linux. Google 'CAD for Linux'
Damn ... quoting myself again.
It would be most helpful for you, if you used the 'search' feature in this or any Help Forum ... first.
Yes, there are several CAD applications 'already' in the Synaptic Package Manager. Easy to install and use.
Maybe, you could also use Google search engine ... "CAD for Linux" .. brings up many many links.