theprintspace fully supports selling limited and open editions, with certificates of authenticity, so editioning your work is well catered for.
When you set up a product as a limited edition in creativehub, you choose the edition size, and that quantity syncs to your store as available stock. Each sale ticks one off the edition and updates the count automatically, and you can attach a personalised certificate of authenticity (with your name, signature and branding) to every piece.
There's also an Editions dialog — open it from the Variants card on the Product page by clicking a variant's Editions sold value — where you can see individual edition numbers and tick/untick each one's Sold box. This is how you mark items as sold or free them up again, and the mechanism you'd use to hold back specific numbers (for example, keeping certain editions out of public sale).
What isn't a distinct, named feature in the standard set-up is a dedicated 'artist proof' (AP) designation separate from the numbered edition. Many artists handle proofs by accounting for them within their stated edition size (e.g. an edition of 25 + a small number of APs) and managing those manually.