You can create markers with duration in Premiere, that may be what you need to do to get the job done today.
And you probably want sequence markers, not clip markers.
Use your keyboard shortcut for "deselect all" (Ctrl/Shift-A on my rig) to make sure nothing is selected, then with playhead where you want to start tap the M key. With the timeline zoomed in some, you can now hold down the Alt key, then click the very upper-right corner of the sequence marker, drag to the right, and let go where you want the marked duration to end.
Alternatively you can hit M to creat the marker, tap M again to open the Markers panel, and either drag the "duration" option in blue to the right to increase it or type in a timecode for the duration needed.
Either way, with sequence markers with duration set, your name for the marker appears on the marker itself at the top of the sequence on the timeline bar. Making it easy to know which is which.
Neil