The asymptor R package allows you to estimate the lower and upper bound of asymptomatic cases in an epidemic using the capture/recapture methods from Böhning et al. (2020) and Rocchetti et al. (2020).
You can install the stable version of this package from CRAN:
or the development version from GitHub:
Please see the vignette for a detailed example using the COVID-19 data from Italy.