> ## Documentation Index > Fetch the complete documentation index at: https://docs.getoneprofile.ai/llms.txt > Use this file to discover all available pages before exploring further. # Where the data comes from > Each enrichment checks several sources in order, keeps the first answer, and charges only for rows that fill. An enrichment is not one database. Each one checks several sources in order and keeps the first answer, so coverage is higher than any single source could give. The Tools panel's Enrichment tab beside a table, listing rows like Find work email, Verify email and Find phone number, each with a one-line description and a price in credits per row. ## One column, several sources When a column runs, each row asks the sources in order until one answers. The first answer wins and fills the cell. Rows the first source misses still get a chance from the rest, which is why fill rates beat any single source. ## What a row costs The price on the catalog row is the whole price. A filled row costs that amount, whichever source answered it. A row no source could answer costs nothing. ## Answers you can act on **Find work email** results are checked against multiple sources, and **Verify email** runs a deliverability check before sending. Verified emails bounce less, which protects your senders. See [Email deliverability](/outreach/email-deliverability) for the sending side. ## Good to know No source had an answer for that row, and nothing was charged. Add a stronger identifier, like a LinkedIn URL, and run the column again. An input the enrichment requires was empty. Skipped rows are never charged. Fill the input and run the column again. No. The order is tuned for coverage and cost, and the price is the same whichever source answers, so there is nothing to gain by choosing. People change jobs and companies change size, so old answers can drift. The run menu's option for out-of-date rows refreshes them when you need it. ## Next steps Add a column from the catalog and map its inputs. Control what runs, when, and over which rows. See where credits go and how to buy more.