It depends on what kind of result you’re measuring. The first month is analysis and strategy: I audit your website and your wider online presence and define the best plan forward. From the second month, delivery begins, and some results are immediate. Fixed technical issues, for example, are trackable right away with no waiting period.
Ranking changes take longer. That clock starts with the first published content: you’ll typically see early movement in Google Search Console (impression share) first, with rankings often beginning to improve around the end of month two or three. The exact timeline depends on the size of your business and how competitive your market is.