EL said in some interview with her and Paul Rudd, that
she was in Infinity War but small size as Wasp but Paul quickly covered over her statement with some humorous remarks. i'm still searching youtube for it.
Spoiler:
Wasp could only have been in NYC or Wakanda during IW, but really her only connection to the Avengers would have been Scott Lang/Antman's friendship with Steve Rogers, who was in Wakanda. i don't think she would have gone to either NYC or Scotland, so if Wasp was in IW, she would've been in the Wakanda Battle with the other Avengers, Bucky, and the Wakanda heroes. could she have fought Outriders or intervened in other ways? was she there solo or was Antman with her? there is also a recurring rumor that there were ants on one of the tables in Shuri's laboratory, in the science wing in Wakanda, during the Outrider battle. still waiting on a screenshot or video of that, but there are multiple sources saying this has been spotted by fans seeing IW repeatedly. if you'll remember, ants are used as spies or intelligence-collecting by Pym and Antman, and may have been monitoring the battle, Shuri's work with the Mind Stone and Vision, or been taking an inventory of available vibranium for use by Hank Pym in creating something to use against Thanos.