If the credit to your wife's benefit in the old employer's plan is above a certain threshold, $5,000, I believe, the old plan cannot require that the balance be moved out, but your wife might want to do that anyway to consolidate retirement savings.
The offset distribution can be rolled over to your wife's new employer's plan if they will accept the rollover (they are not required to do so), or to an IRA. To roll it over to the new employer's plan, contact that plan's administrator for instructions and confirmation that they will except the rollover. Otherwise she can contact any IRA custodian and open an IRA to receive the rollover.
From your response it's not entirely clear, but I believe that your wife has received a 2019 Form 1099-R reporting this distribution. Simplest will be to complete the rollover before April 15 so that in the questions that follow entering the details of this Form 1099-R into TurboTax you can say that the distribution was rolled over to another retirement account and indicate the amount rolled over. Otherwise, request a filing extension to extend the deadline to October 15. There is no difference between reporting the rollover of an offset distribution and reporting the indirect rollover of any other distribution. Probably much easier than finding a competent tax professional unless you are generally uncomfortable preparing a tax return under any circumstances.
