On the Claude app, go to Customize, then Skills. Hit Browse to grab ready-made skills from the gallery, or hit Add to create one with Claude, write the instructions yourself, or upload a skill file. In Claude Code, use the plugin marketplace: run /plugin marketplace add anthropics/skills, then /plugin install document-skills@anthropic-agent-skills. Skills work the same across the app, Claude Code, and the API.
1. Document skills (pptx, xlsx, docx, pdf). The highest payoff for non-coders. Claude builds real PowerPoint, Excel, Word, and PDF files, not text you copy out. Add them from Customize, then Skills (they're in the Browse gallery).2. skill-creator. The skill that builds other skills. Say "use skill-creator to build a skill that does X" and it scaffolds a custom one for you, no code.3. Superpowers (by obra). Turns Claude Code into a disciplined builder that plans before it codes, so your first app or automation holds together. Add the obra/superpowers marketplace, then install superpowers.4. A marketing skill pack. For ad copy, SEO, and content workflows. Pick a specific one from a curated list (below) rather than a vague "marketing skills" label, since quality varies.5. An awesome-Claude-skills directory. Your app store for the rest. Browse the curated list and add what fits your work.
Anthropic Agent Skills doc
Official skills repo
Claude Code skills docs
Start with the document skills, they change the most day one. Then add skill-creator so you can build your own for the niche things you do over and over. Add the marketing pack last and test it on a real task before you rely on it.