[X-SW] HELP please, opening attachments.

[Rupert Hoyte]

I receive a number of ATTACHMENTS to emails which are represented by a rectangle, containing a small blue square, with question mark.   About a third of these will open,  but the rest do not.  Can you suggest the specific programme, or facility,  which I can download into my Mac to enable me to open them all.   I usually download the latest Adobe help when offered,  but obviously dont have the full range, or whatever I need.    Thank you.  R.Hoyte    .In any reply please give me the full number of steps,  as I am not a computer expert.