In most cases, providing the author's last name and the publication year are sufficient:
Smith (1997) compared reaction times...
Within a paragraph, you need not include the year in subsequent references.
Smith (1997) compared reaction times. Smith also found that...
Two authors
If there are two authors, include the last name of each and the publication year:
... as James and Ryerson (1999) demonstrated...
... as has been shown (James & Ryerson, 1999)...
3 or more authors
If there are three or more authors, include the last name of only the first author followed by "et al.":
Wottom et al. (2017) found that...
... was also noted (Wotton et al., 2017)...
Corporate authors
The names of groups that serve as authors (e.g., corporations, associations, government agencies, and study groups) are usually spelled out each time they appear in a text citation. If it will not cause confusion for the reader, names may be abbreviated thereafter:
First citation: (National Institute of Mental Health [NIMH], 1999)
Subsequent citations: (NIMH, 1999)