Denise has opened a party shop and acquires many of the items that she is selling in her party shop from another country. This is an example of

Importing

Explanation:

Importing -

It is the method by which some goods and services are sold in a specific country, which are initially bought from any other country, is referred to as the process of importing.

In this case, some good quality, low price are bought which are sold at higher price, to earn profit margin.

Hence, from the scenario of the question, Denise is practicing the process of importing.