Question

draw the structure of all products of the mechanism below.

Explanation:

Step1: Identify the reaction type

This is an acid - base reaction where the carbonyl oxygen of the carboxylic acid is protonated.
The oxygen of the carbonyl group has a lone pair of electrons and can act as a base to accept a proton ($H^+$).

Step2: Draw the product structure

When the carbonyl oxygen is protonated, the product has a positive charge on the oxygen atom. The structure of the product is:
$H_3C - C(=O^+H)-OH$

Answer:

$H_3C - C(=O^+H)-OH$