What's the difference between SEO and PPC methods?

The main difference between Search Engine Optimization (SEO) and Pay Per Click (PPC) is that traffic coming from SEO (organic) is free while traffic generated from PPC is not free (as the name implies you have to pay a cost per click).

The main difference between Search Engine Optimization (SEO) and Pay Per Click (PPC) is that traffic coming from SEO is free while traffic generated from PPC is paid.

SEO or search engine optimization is the process of optimizing your website in search engines. The process helps to build your online identity and reputation to benefit your online business.

PPC stands for pay-per-click, a model of internet marketing in which advertisers pay a fee each time one of their ads is clicked. Essentially, it's a way of buying visits to your site, rather than attempting to "earn" those visits organically. Search engine advertising is one of the most popular forms of PPC.

PPC is a paid advertising and is mainly used for the purpose of generating leads and revenue in a short amount of time.
SEO is a free technique and is used for promotion and branding purposes.It takes a long time to get the expected results.