  We analyze various tracers of magnetic activity for 23 solar twins which are
characterized by significant scatter of lithium abundance in their atmospheres.
A level of coronal and chromospheric activity has been studied from available
X-ray and UV-archival data. It gives us a chance to compare coronae of solar
twins of various ages with the solar case. We found a scatter in the X-ray to
bolometric luminosity ratio $L_X/L_{bol}$ by several orders of magnitude, which
exists in these stars along with a significant spread in Li abundance. This may
link the surface activity of stars with phenomena at the base of their
convective zones. The TESS data allowed us to reveal rotation modulation of
stellar brightness associated with starspots. For some twins of our samples,
periods of axial rotation are detected around 6 days, i.e. these stars rotate
almost 4 times faster than the contemporary Sun. This indicates their relative
youth. Flare activity of solar twins is discovered in the TESS data; we showed
existence of various kinds of flares, and present temporal profiles for some of
them. We obtained the energy about of $8 \times 10^{33}$ erg for the largest
flare of our samples, lasting longer than 4 h. In addition, we discuss also
magnetic fields and exoplanets, orbiting these stars.
