Default font used by software

Dear members, could you please tell me what is the default font that is used when I create a paragraph and copy content in it without specifying font?

it depends on the bootstrap theme you're using (setting/manage themes). Default is defined in bootstrap.min.css as font-family- -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol" and you check it using Chrome developers tools

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