Most lamas will give their students a PDF of the specific sadhana they are to practice. This is the only fully legitimate source. For example, His Holiness the 41st Sakya Trizin, or prominent Karma Kagyu lamas such as Khenpo Karthar Rinpoche (before his parinirvana), have issued authorized translations.

The content of the PDF depends heavily on the lineage:

Some texts, like The Chakrasamvara Root Tantra or The Practice of Vajrayogini (by Thubten Chodron and His Holiness the Dalai Lama), contain sadhana elements. However, these are often published as explorations for initiates, not as standalone "read and recite" PDFs.