

You can tell the letters underlined in red are San Serif because they don’t have little lines at the end of each letter. The I is straight up and down for example that proves that there is no serifs.
You can tell the letters underlined in blue are script because they are very fancy and more focused on making them look good than how it reads. The G for example has a little line that goes around the word to make it look better. At the same time this looks cool but makes it harder to read.
These two element make this typography because while it is easy to read. If Script was the title font it would be very hard to read. That is why San Serif is the title while the script is the sub line.
These elements in this pictures can help you make better designs because it shows that fonts on a document matters. There is a reason they put San Serif as the title and script as the sub line because it is easier to read.