There are many online tools like this one (https://toolama.com/convert-letter-case) available that can convert text to different cases with just a few simple steps. You can copy and paste the text into the tool, and then select the desired case conversion option (e.g. upper case, lower case, sentence case, etc.).

Capital and small letters

Upper case are usually used for the following:

• the first letter of a sentence;
• proper names and adjectives, such as names of people, places and organisations;
• acronyms and initialisms;
• titles and headings;
• emphasis or to convey a strong feeling in some contexts, such as shouting.

It is important to note that different style guides and writing conventions may have slightly different rules about when to use capital letters.

Lower case is usually used for the following:

• most words in a sentence, including common nouns and verbs;
• conjunctions, prepositions and articles;
• adjectives and adverbs that do not precede the noun they modify;
• in some contexts, such as web addresses, email addresses and file names, to make them easier to read.

That different style guides and writing conventions may have slightly different rules about when to use lowercase.

But what about random case?

"Random case" refers to a style of writing in which the case of the letters in a word or phrase is chosen at random, rather than following traditional rules of capitalisation.

This style is often used to make text stand out or to create a visually interesting effect, but it can be harder to read.

It is not widely used in formal writing and is most often used to create a visual effect or joke in an informal setting, such as memes, captions or social media posts.