The word archives can be used in three different ways:
Excerpted from The Story Behind the Book: Preserving Authors’ and Publishers’ Archives by Laura Milla
Additionally, there are some related points to consider.
Some archival collections are stored only in archives or repositories. The only way to interact with those materials is by appointment. You would access a finding aid to note which objects/artifacts/etc you need for your research. After that, the materials would be brought to you in a reading room -- a dedicated space solely for this purpose.
Other archival collections have been digitized. This means that, if you use the example from the above case, some of those same materials -- otherwise accessed only by appointment, at a specific place -- have been made available electronically. This could mean that photos have been scanned, for example.
Other archival collections may be digital archives. This tends to refer to collections of materials that were "born digital." Those would be things that don't exist outside the Internet, like videos, social media posts, websites, etc.
When dealing with digital archives, it may be useful to think of them as databases that allow you to search primary sources.