How to get tax code from Account entity?

Hi Experts,

I am newbie in this Dynamics CRM 2016 Online. I have requirement to get tax code from Account entity.

Situations, user enter Quote from Opportunity form. User press '+' and new form of Quote come out. In Quote form, Customer Tax Code must have value of tax code (SR, TX or etc). This tax code a retrieve from Account entity based on AccountID. One of member in CRM community suggest me to define the plugin with message is Associate to implement and map the tax code and tax rate. But how can I do it? Can someone help me to this issue?