How to see pictures in your text messages I have done what was posted before. When I tape the download button it doesn't download
Ensure your mobile data is on and that roaming is switched on. As I do not know your operating system I will post instructions for marshmallow. 

Settings > mobile networks > data roaming

EDIT:
based upon the newly supplied facts I viewed you need to change you apn login details as seen on this website.

Navigate to 
Settings>More>Mobile networks>Access Point Names>Menu>

Once there delete any currently present apn profiles then restart (hold down the power button until the menu including a shut down button appears).

Once turned back on navigate back to the apn menu. 

Enter these details in a new profile

APN: tfdata
MMSC: http://mms-tf.net
MMS proxy: mms3.tracfone.com
MMS port: 80

Save and restart once more. 

Your MMS should now work.