While you can certainly use Amazon S3, Azure, and other file hosting services to store your .hic files, Dropbox works just as well and is quite easy to set up!
We'll go through a quick tutorial so you can see how easy it is to share results with your collaborators.
We've uploaded sample files to https://www.dropbox.com/sh/inf1f96r5io5io6/AAAa95E6NXSWKHKxLp2dy4p8a?dl=0
The first step is to upload your file to dropbox, and then copy a link to the .hic file.
For this particular example, the following file link was created: https://www.dropbox.com/s/u2m6dm7putuwr58/imr90_intra_nofrag_30.hic?dl=0
Load Map → URL
Paste the URL copied above into the text box and hit enter
The map will then load. You can do everything you would do with a .hic file. You can also upload your 1D and 2D annotation files to Dropbox and load them into the visualization using
Load Tracks → Track URL. Share links can then be generated; here's a fully Dropbox hosted link: https://tinyurl.com/y8996w5r
If you're interested in published data from a paper that performed Hi-C experiments, you can see if they've uploaded their processed data to GEO. For example, let's look at this series: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE104333
Scroll down and right-click the ftp link next to the file 180min_withdraw_combined.hic
Now go to a fresh instance of Juicebox and click
Load Map → URL. Paste the link address you just copied. As with Dropbox files and any other URL, you can use Juicebox as you normally would.