Hi,
It is easy.
Data input-ed in the web interface will be usable in the process.
In widget configuration you specify the variable name in the properties, and you can get the values with that variable name.
For example, if you had a array widget with variable my_array, then in process you can get it by ${my_array}.
This can be used anywhere in your email message, like,
Dear ${P_initiator.login},
Your array input is ${my_array}.
Please refer to this forum topic for details about using array variable in process:
Best regards,
Taka