How to parameter the ports in move tank block EV3? How do I parameter the ports at Move Tank block (in My Block)?
Create a My Block that looks something like this:

Then you can select the ports like this:

The 23 means ports B+C (see below).

From the help file:

Wired Input of Two Ports
If you configure a Move Steering or Move Tank block for wired port input, you will need to specify two different port numbers: one for the left motor port, and one for the right motor port. This is done by using a two-digit number for the Port input. The first digit of the number (the 10’s digit) specifies the port number for the left motor, and the second digit (the 1’s digit) specifies the port number for the right motor.
EV3 Motor Ports
(Left, Right)     Value of Port input
-------------------------------------
B, C              23
C, B              32
A, B              12
A, D              14 

See the table above for the individual motor port number values. The table below shows some examples of Port inputs to specify two ports.