Windows 95 and 98/98SE shipped with Microsoft Fax, buried in the Add-Ons folder of the OS install disk. With ME, it was eliminated, and generally won't work reliably even if you can find it - in fact, it may cause system stability errors, so don't even go there. Its possible the computer's modem software bundle includes a fax utility; many do, but many don't. Its worth browsing the modem's install disk, if available, or visiting the modem vendor's website to see if a fax utility for that modem exists. A freeware 3rd party fax utility that works OK, even if it isn't very robust, is
V3 Call Center. A $30 upgrade to the "Pro" version will get you more features, but the free version is adequate for simple send-and-receive stuff. Naturally, a modem connected to an active phoneline is gonna be necessary, and fax operations can be carried out only when the modem and phoneline are not otherwise in service, such as connected to The Web or conducting a voice call. There may be issues with call waiting, voicemail, and distinctive ring services; its best to turn them off, if you have them on your phoneline, while conducting phoneline fax operations. Instructions for de-activating/re-activating call waiting, voicemail, and/or distinctive ring services are available from your telephone service company - often printed in the front pages of your phonebook.