Made in USA vs Made in the USA [duplicate]

Solution 1:

The definite article does appear before the names of certain countries:

• "The USA"
• "The United Kingdom"
• "The Russian Federation"
• "The (former) Soviet Union"
• "The Republic of South Africa"
• "The Bahamas"
• "The Ivory Coast"
• "The Philippines"
• "The Netherlands"
• "The Gambia", just to mention the most important ones.

Therefore, you should use the article when you write "made in..." although it is often omitted on labels.

references:

1. When to use "the" with country names
2. The Definite Article

corrigendum - An ngram search charts "Ivory Coast" much more frequently than "The Ivory Coast"

Solution 2:

Omission of articles and conjunctions is common in any kind of telegraphic English, that is, the highly compressed language of newspaper headlines (see headlinese), diaries, road signs, sports calling, text messages, and so on— product labels included.

Both Made in USA or Made in the USA are fine in that regard, interpreted to mean Manufactured in the United States of America. You can find examples of other countries, as well, e.g. Made in ROC/Made in PRC for goods from the Republic of China (Taiwan) and from the People's Republic of China respectively.