%s

or conversion specifiers are sort of like a placeholdes for strings

In [1]:
Name = 'Friend'
In [2]:
Place = 'world'
In [3]:
'Hello %s, you are invited to travel around the %s with %s, bring %s with you.' %(Name, Place,'me', 'food')
Out[3]:
'Hello Friend, you are invited to travel around the world with me, bring food with you.'