Download tachiyomi, it's not on the apple store so Google search it and download the apk file. Then on tachiyomi just install mangasee and search one piece. There'll be a digital colored edition. It goes up to chapter 940ish I think.
Since you're using an apple device it'll be harder to download third party apps but there should be work arounds that you can find on YouTube. It'll just require more effort and steps. On Android it's as simple as just downloading it. If you can't download tachiyomi on iOS then try mangarock or mangastorm, but I'm not sure if they let you download manga.