For QGIS or ArcGis Pro /// Would you know how to use an external url as a background map (from a specific url, see comment)? – February 13, 2023 at 06:15PM

You can use some URL, like from google, osm, esri as such, using WMS or XYZ tiles. Or some extentions that does that already

But, would you know how i could use, extract or find the specific URL needded from this free provider: https://www.geoportail.gouv.fr/donnees/cartes-1950 ? Because i didnt managed to make it work with the link alone