To form adjectives from geographical names, you typically add a suffix to the name of the country or region, though some geographical names have unique adjectival forms that are established through common usage. Here are the adjectives formed from the geographical names you've listed:
Spain - The adjective form is Spanish. This is used to describe anything related to Spain, such as Spanish food, Spanish language, or Spanish culture.
Australia - The adjective form is Australian. This term is used to describe things associated with Australia, like Australian animals, Australian cities, or Australian accents.
Great Britain - The adjective form is British. This describes anything pertaining to Great Britain, including British literature, British politics, or British people.
Japan - The adjective form is Japanese. This is used for items or concepts related to Japan, such as Japanese cuisine, Japanese art, or Japanese technology.
Italy - The adjective form is Italian. This is commonly used to describe things connected with Italy, like Italian music, Italian food, or Italian fashion.
France - The adjective form is French. This adjective describes anything related to France, including French wines, French language, or French history.
The United States of America - The adjective form is American. This is used in contexts related to the United States, such as American culture, American politics, or American sports.
These adjectives are quite useful for describing the culture, people, and products of these respective countries and regions.