Grouping related data
When a value is more than a single number — a user with a name, email and age — you want to bundle the fields together under one name. HTML provides objects (or structs / records / dictionaries depending on the language) to do exactly that.
<form>
<label>Name <input name="name" required></label>
<label>Email <input type="email" name="email"></label>
<button>Submit</button>
</form>Methods
Many languages let an object carry not only data but also functions ("methods") that operate on that data. This style is called object-oriented programming and is the dominant way to organise large programs.
When to make a new type
If you find yourself passing three or four related values into every function — say x, y and z of a 3-D point — that is a clear signal to introduce a new object type that holds them together. The code becomes shorter, safer and easier to extend.