We can usenowadays, these daysortodayas adverbs meaning ‘at the present time, in comparison with the past’:
I don’t watch TV very muchnowadays. There’s so much rubbish on. It’s not like it used to be.
Young peoplenowadaysdon’t respect their teachers any more.
Take care to spellnowadayscorrectly: not ‘nowdays’.
These daysis more informal:
These daysyou never see a young person give up their seat for an older person on the bus. That’s what I was taught to do when I was a kid.
Pop singersthese daysdon’t seem to last more than a couple of months, then you never hear of them again.
Todayis slightly more formal:
Apartmentstodayare often designed for people with busy lifestyles.
We can usetoday, but notnowadaysorthese days, with the possessive’sconstruction before a noun, or withofafter a noun. This use is quite formal:
Today’sfamily structures are quite different from those of 100 years ago.
The youthof todayhave never known what life was like without computers.
We don’t usenowadays, these daysortodayas adjectives:
Carsnowadays/these days/todayare much more efficient and economical.
Not:The nowadays cars / The these days cars / The today’s cars…