Are there some page view etc. limits while using an embedded iframe map from openstreetmap.org?
For example could a page with 1000 visitors per day show an iframe with a map showing a single marker?
The embed code could be similar to this: <iframe width="100%" height="350" src="https://www.openstreetmap.org/export/embed.html?bbox=2.272453308105469%2C48.850992515964585%2C2.316656112670899%2C48.865223017642414&layer=mapnik&marker=48.858108272503905%2C2.2945547103881836"></iframe>
There are no use restrictions I’m aware of as long as attribution is given. I.e. there is some way to tell (usually on the bottom right) that the map is from OpenStreetMap (OSM).
If your site generates a lot of traffic for OSM and you profit from that somehow, you are most welcome to make a donation to OSM, though that’s for you to decide. OpenStreetMap is free to use for everyone.
“Fair use” is probably not the correct term as it is about rights in content, whereas what you’re asking is “how much load can I put on OSM’s servers” and the following policy explains that a little (while not giving concrete numbers): Tile Usage Policy
The web site https://switch2osm.org has instructions on how to set up your own tile server. You could also investigate making a static image of the map with the marker and host that on your platform - of course this doesn’t give the user the option to zoom and pan, but you’d not make any tile requests from OSM when the page is served.
Another thought could be whether it is necessary to have an iframe. If it never changes, might it be easier for everyone if it’s just a PNG? Perhaps in combination with a link to the location in OSM if necessary.
The background still needs attribution, but there is no load for OSM at all and I personally always appreciate less connections over the internet, regardless of destination.
In this case, the map would appear as part of the customer service points’ contact information. Therefore the map info of the surroundings are essential.
The map you see with all the icons, streets and environment, is made up of tiles (which you can see load in when looking around). These tiles come from the tile server, so the tile usage policy is relevant. If you need a legally binding answer, it’s the best source (and only authoritative one).
My answer is a non-legal explainer that’s probably a bit easier to understand.