Domain seo vs subdomain

[dhanson24]

when building links is it better to link to the main domain (www.aabbccarpetcleaning.com) or www.aabbcccarpetcleaning/carpet-rug-cleaning

[GastonRiera]

Hello there!

There is no definite answer for your question. It does completely depends on your strategy. 
So if your homepage is optimized for one keyword, then when creating backlinks with that kw point them to the home page.
Otherwise, use a landing page created specually for that.

REMEMBER, google does not want (even, doesnt like) us to create several pages nearly identical just for targetting different keywords that are very similar.
More info: Doorway pages - Google Search Console Help and Google Defines doorway pages, John Mueller - SERT

Hope it helps you.
Best Luck.
GR