Is it possible to upload tracks to Strava?
Yes, you can upload your tracks to Strava. If your device is connected with Garmin Connect, there is an option to automatically upload your tracks after they're synched with the Garmin platform.
If you don't want to connect your device to Garmin Connect, an alternative is to manually upload the recorded GPX files in Strava. I would except the files to be stored in the Garmin/GPX folder, which is visible after you connect your device to your PC.
Next, on the Strava website click the + in the right top, chose upload and click "File" on the left column. The upload interface allows to upload multiple files at once.
Are segments visible on your display?
As far I'm aware, the Oregon 700 does not have Strava live segments available. However, when I was using the Oregon 400, I used a small trick to visualize them on the map.
If you download a GPX of a segment (eg. using this Chrome plugin), you can upload the segment as a track on your device. Next, in the track manager I could chose to show this particular track (being the Strava segment) on my map. Even while navigating another
route or track While cycling, this segment was visible on the map. I didn't got any notifications for the start or end of the segment and had to spot them manually, but at least you know where to push as hard you can.
I couldn't find the exact steps in the Oregon 700 manual and don't have one myself to guide you, but this might already give you a good pointer.