Create folder, then put the relevant documents into that folder and wait for them to sync.
Get person on the phone... "What's your email address?"
Share folder with them and tell them they will have 30 minutes to download it.
Remove their access to the folder - rinse and repeat to new person(s) as required.
Unless you actually want to provide the document in a protected format, this avoids all issues with software compatibilities and is pretty secure, except for what the recipient might do with it after they have it, but then if they have been able to decrypt it with their personal key, then they could take screenshots if nothing else to compromise your security...
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Create folder, then put the relevant documents into that folder and wait for them to sync. Get person on the phone... "What's your email address?" Share folder with them and tell them they will have 30 minutes to download it. Remove their access to the folder - rinse and repeat to new person(s) as required. Unless you actually want to provide the document in a protected format, this avoids all issues with software compatibilities and is pretty secure, except for what the recipient might do with it after they have it, but then if they have been able to decrypt it with their personal key, then they could take screenshots if nothing else to compromise your security...