So you purchased a painting on a wood panel or canvas panel--now what? Here are some options.*
Don’t frame it. I get sawtooth hangers at the hardware store. Measure to find the center of the panel. Glue the bracket on. (I use a hot glue gun.) Drive a small nail into the wall. Hang it up. The painting hovers on the wall, very modern looking. If you decide to frame it later, you can easily remove the sawtooth hanger.
Frame it in a traditional frame. Ready-made traditional frames are widely available, in a variety of finishes and styles. Acrylic and oil paintings should not be framed behind glass. Collages, watercolors, and drawings should be protected behind glass or plexi.
The only drawback to a traditional frame is illustrated above. The red line shows how much of this 12 x 12 inches painting was obscured behind the frame's edge. The larger the painting, the less of a big deal this is. But if your painting is small and has details near the panel's edge, this might be a problem.
Frame it in a floater frame. A floater frame leaves at least a 1/8" gap between the frame face and the painting's edge, so no details are lost behind the frame's front edge. You will not usually see ready-made floater frames in retail stores, but they can be found easily enough online. (I have some links below.)
Keep a close eye on the depth (or rabbet height), though, when you are shopping. Ideally you want a 3/8" depth (rabbet height), but that is difficult to find in a ready-made frame. A wood or canvas panel will work fine in any frame with a 7/8” depth (rabbet height) or less. Know that with a deeper rabbet, your image will take on some shadow.
The main drawback to using a floater frame is the level of difficulty involved in mounting the panel in the frame. Ampersand, an art materials manufacturer, has put together an instruction sheet for framing with floaters. -- https://ampersandart.com/pdf/Ampersand-floaterframe-Instruction-Sheet.pdf
Floater frames around the web:
Affordable black floater frame -- https://www.webpictureframes.com/product4/3442/black-panel-floater-frame.html?action_id=set_artwork_size&action_data=6,6
Unfinished 3-pack of 6 x 6 inches floater frames on Etsy -- https://www.etsy.com/listing/684506877/tile-float-frames-6x6-unfinished-for
Variety of brands and finishes available from Blick -- https://www.dickblick.com/categories/framing/frames/float/
Available in many different finishes on Amazon -- https://www.amazon.com/Square-Floater-Canvas-Paintings-Stretched/dp/B08BH6DJ6J?th=1
My personal favorite online frame source is Franken Frames. A note about ordering a custom-built frame, though. You will need to add 1/4" to the dimensions of the artwork to make the float space. -- https://frankenframes.com/frame_ccs.php?Frame_id=674
Take your artwork to a professional framer. And if you're going this route, I urge you to find a small, local custom frame shop to support, rather than a large corporate chain. I always have a much better experience, on a human level, when I work with an independent craftspeople. (Lynn Atkins Custom Framing is my cousin's shop in Manteo, North Carolina. She's amazing!!!)
*All of the links are suggestions, not endorsements. (Except Lynn--she is the best!) This blog post is not sponsored or a paid advertisement or anything like that. Just some helpful tips for my collectors.