Examples of proper nouns:
Persons: Names (e.g. John, Mary, Muhammad)
Titles (e.g. President Biden, Queen Elizabeth II)
Places: Countries (e.g. France, Brazil, Japan)
Cities (e.g. New York, London, Tokyo)
States (e.g. California, Texas, Florida)
Streets (e.g. Main Street, Fifth Avenue)
Landmarks (e.g. Eiffel Tower, Great Wall of China)
Things:
Organizations (e.g. United Nations, NASA)
Companies (e.g. Apple, Google, Microsoft)
Brands (e.g. General Motors, Nike, Adidas)
Books, films and songs (e.g. Harry Potter, The Lord of the Rings)
Days of the week (e.g. Monday, Tuesday, Friday)
Months of the year (e.g. January, February, March)
Holidays (e.g. Christmas, Thanksgiving, Diwali,Ramadan)
Important points to remember: Always capitalize the first letter of a proper name. Some proper nouns consist of several words, and each important word should be capitalized (e.g. United States of America, New York City). Over time, some proper nouns can become common nouns (e.g. Xerox, Kleenex). Understanding proper nouns will help you improve your writing and speaking skills.
Do you have any further questions about proper nouns or English grammar in general?