Increasing storage of Envy Notebook 15-as050na or upgrade?

[SMiLEYSMiLE1]

Hi guys, I need help. I have the above laptop and I don't have much storage left in C drive. I have had to use D drive to hold precious photos and videos of family. I believe I have 8gb RAM and 128gb solid state drive plus 1TB hard drive.

I am not the brightest when it comes to figures on why for instance me C drive is almost full. I do use external HDn.  to store my photos/videos. I also like to keep them on my laptop but I believe I have quite a few duplicates. Can someone recommend a really easy to use duplicate finder software? So many to choose from.

I would be grateful for advice on what is exactly my 128gb? I this the C drive? The D drive being the 1TB? The properties suggest this. Can I increase the SSD and HD capacity or would I be better upgrading to another laptop? I do not use my laptop for games.

I do use my smartphone a heck of a lot more but I still want a portable PC. There's so much out there. 

So, what are my choices? What is the maximum storage I can have? This laptop is a 15" screen. I am happy to look for a smaller screen. Then I can take it on my travels. Look forward to feedback. Thank you in advance.

[Huffer]

The official specs for your laptop as originally configured by HP only mention the 1 TB 5400 rpm 2.5 inch SATA mechanical hard drive. 

On the model series, however, there were options for an M.2 SSD aka gumstick drive. I assume you have a 128 gig M.2 SSD as the C: drive and then the original 1 TB 5400 rpm mechanical hard drive as the D; drive. There is no problem in keeping the photos, documents and such on the hard drive. In fact, that is what it is designed to do. 

One very easy thing to do which will instantly free up space on the C: drive is to relocate the "Library" files to the  "D" drive. That is the standard Windows "documents" "photos" "videos" and "downloads" folders. This is where a lot of stuff accumulates. This tells how to do that:

https://www.pcworld.com/article/419271/move-your-windows-10-libraries-to-a-separate-drive-or-partiti...

Yes, you could install larger capacity disks and if you can do the work yourself it would cost a fraction of a new laptop. However, 1 TB is a pretty big storage space and may be enough for you if you can slim down the C: drive. This also means you have your "system" and "data" separated so that any crash of the system drive does not also take down your data. You also want to consider having a backup of everything on an external drive. A lot to digest here and I will leave off and invite any further questions you may have.