SEO (Search Engine Optimisation) is the practice of Optimising a website to improve its ranking and visibility in search engine results pages (SERPs). The goal of SEO is to increase organic, non-paid traffic to a website by making it easier for search engines to understand the content on a website and to index it properly. SEO involves a range of technical and creative techniques, including keyword research, content creation, link building, and site architecture Optimisation.

SEM (Search Engine Marketing) is the practice of using paid advertising on search engines to reach potential customers. SEM involves creating and running ads that appear in search engine results pages (SERPs) when people search for specific keywords or phrases. Advertisers pay each time someone clicks on their ad, hence the name "pay-per-click" (PPC).

SEO and SEM are related, but distinct, practices. While SEO focuses on improving a website's ranking in organic search results, SEM involves using paid advertising to reach potential customers. Both practices can be used to improve a website's visibility in search results and to drive traffic to a website, but they are executed differently and may have different goals and objectives.

Here are the basic steps to get started with SEO and SEM:
1. Conduct keyword research: Determine the keywords and phrases that potential customers are using to search for products or services like yours.
2. Optimise your website: Make sure your website is properly Optimised for search engines, including technical elements such as site architecture, content, and meta tags, as well as creative elements such as content quality and relevance.
3. Build high-quality links: Establish high-quality links to your website from other reputable websites, to demonstrate the authority and credibility of your site to search engines.
4. Create SEM campaigns: Develop targeted SEM campaigns to reach potential customers through paid advertising in search results pages.
5. Monitor and track results: Use analytics tools to track the performance of your SEO and SEM efforts, including search engine rankings, traffic, and conversions.
6. Continuously improve: Based on the results you are seeing, make changes to your SEO and SEM strategies to continuously improve your results.

SEO and SEM are complex and ever-changing fields that require ongoing effort and commitment. However, by using best practices and tracking results, companies can improve their visibility in search results and drive more traffic and conversions to their websites.