I'm looking for a tool that makes it easier to share things like SSN, passport info, W2s, I9s, etc...
- I prefer using something like DottedSign - it's an e-signature app that's highly secure and sending sensitive documents, signing contracts/agreements etc., takes very little time, while all the information is encrypted and with a paper trail, all the changes are recorded as well. A great option for when you need to send out and sign all kinds of documents quickly and efficiently.
- Dropbox has built an alternative to Google Docs, but cleaner with a better experience. It is integrated deep into your Dropbox Cloud and secure. You can invite folks with a special link to your doc, so they can edit & comment (all optional).
- Big names like Dropbox or Google Docs should be good enough, given you've secured your login credentials with 2-factor authentication etc. They also have dedicated security teams which smaller players may not have. You can add extra security by encrypting your files before putting them in the cloud.