Do you mean “SEIS” as the UK Seed Enterprise Investment Scheme (SEIS), or a company/brand named “Seis” (e.g., a product or service), or something else (for example Spanish seis = six)? Each meaning leads to very different, specific customer-service guidance. Tell me which one you want and any target audience (startups, investors, internal support teams, region), and I will produce the requested detailed HTML content.