"Peter's grandmother has come from Delhi today."
Translation:पीटर की दादी आज दिल्ली से आयी हैं।
पीटर की दादी आज दिल्ली से आयी हैं। = Peter's grandmother has come from Delhi today - Present perfect tense
पीटर की दादी आज दिल्ली से आयी। =Peter's grandmother came from Delhi today - Simple Past tense
Side note: The English letters 'T' and 'D' in 'Peter and 'David' are transliterated as ट and ड in Hindi because they are pronounced as retroflex letters in Indian English. So, Peter would usually be written पीटर instead of पितर.