The titles of software and apps should be italicized in the reference list entry but not italicized in the text.
In-text citation
(Author or Name of group, Year of publication)
(Viechtbauer et al., 2019)
Author or Name of group (Year of publication)
Viechtbauer et al. (2019)
Reference List
Author, A. A., & Author, B. B. (Year of publication). Title of work (Version X) [Computer software]. Publisher. http://xxxx
Viechtbauer, W., Dewey, M., Henmi, M., Weiss, B., Hoeksema, J., & Cheung, M. (2019). The metaphor package: A meta-analysis package for R (Version 2.1-0) [Computer software]. The R foundation. http://www.metafor-project.org/doku.php/metafor