In order to be able to make a connection from a device to an OpenVPN server, it is necessary to have an OpenVPN client program installed. If your OpenVPN client program is installed but has no instructions yet on what server to make a connection to, and how to do so, with which certificates and encryption ciphers and so on, it is at that point basically useless. It needs configuration in order to be able to do its job. With the OpenVPN programs, this configuration can be provided to the OpenVPN client program by giving it a text file that contains the necessary information.
With the open source project, it was and still is quite common to see a .conf text file that contains the necessary OpenVPN directives, and if necessary, it references extra files that come with the .conf file that contain private keys and public keys (certificates) that are used for authentication purposes. It is not uncommon to have a collection of such files, each with their own purpose, and all centrally referenced by the .conf file. Such an open source configuration profile could consist of for example these files, but this is merely an example:
Nowadays it is possible to incorporate these separate files into one text file that contains all of these separate files. This makes it easier to import such a connection profile. The term configuration profile and connection profile are interchangeable, they mean the same thing, a file or set of files that contains all the configuration needed to establish a connection to a server.
If you use OpenVPN Access Server, we prefer to use this new unified format, and we have given this file the extension .ovpn. So when you go to the client web interface of the OpenVPN Access Server, it is possible to log in and obtain a connection profile there, and it would be called client.ovpn by default. This file, when loaded into a suitable OpenVPN client program, will contain all the necessary instructions for the program to make a connection to the OpenVPN Access Server. Normally however, if you use OpenVPN Access Server, you instead just download the OpenVPN Connect Client for Windows or macOS, and install it on your Windows or macOS device, and it comes preprogrammed with the required instructions. This is a function of the OpenVPN Access Server, and when you download a copy of OpenVPN Connect Client separately from our openvpn.net website, it will obviously not contain any instructions to make a connection to your server. Only your own OpenVPN Access Server can bundle such instructions automatically.