Thank a lot  qbteachmt

You really answered my question

Reason: I am preparing 2019, tp contributed $6500 traditional IRA 2019 (couple $12000), and subject  AGI threshold and not IRA contribution deduction. Tp  converted to ROTH 2019. 

He got 2019 1099R distribution of traditional IRA 

I prepared 1040 and attach form 8606,non taxable income  distribution $6500 subject to basic cost of non taxable income and  ROTH conversion (from traditional IRA to ROTH IRA)

Now I am preparing amended 2018 and saw form 5498 and not see 1099R . Tp said  traditional IRA 2018 contribution $5500 (couple $11000). On the 2018 return (tp prepared original) no IRA contribution deduction because of AGI threshold

If he did not convert to ROTH, and keep traditional IRA $5500 ($12000 couple ) as is,  then does tp get penalty? 

I made research, it is likely that no penalty

Per your answer, I feel more confident "OPTIONAL"

Tp can keep traditional IRA and no need convert to ROTH