@AuraEnabled(cacheable=true)
    public static Account getAccRec(String accId){
        Account AccObj = new Account();
        AccObj = [select id,Floor_Plan_Providers__c	,Name,BillingStreet,BillingState,BillingCity,BillingCountry,BillingPostalCode from Account where id=:accId Limit 1];
        return AccObj;
        
    }
===================================================================


<template>
    <lightning-quick-action-panel header="Edit Fields Action">
        <lightning-record-edit-form record-id={recordId}
                                    object-api-name={objectApiName}
                                    onsuccess={handleSuccess}>
            <!--<lightning-input-field field-name="Name"></lightning-input-field>
            <lightning-input-field field-name="Phone"></lightning-input-field>-->
            <!--<lightning-output-field field-name="Floor_Plan_Providers__c"></lightning-output-field>
            <lightning-input-field field-name="Floor_Plan_Providers__c"> {toEmail}</lightning-input-field>-->
             
            <lightning-input type="text" label="Email" value = {toEmail}></lightning-input>
            
            <lightning-input type="text" label="Subject" value="FP_Lead_Email_Notification" ></lightning-input>
          

            <lightning-input-field  label = "CC"></lightning-input-field>

=================================================================

import { LightningElement, api, wire } from 'lwc';
import { getRecord } from 'lightning/uiRecordApi';
import getAccRecord  from '@salesforce/apex/emailController.getAccRec';
export default class sendEmail extends LightningElement {
    @api recordId;
    accounts;
    toEmail;

    @wire (getRecord, {accId: '$recordId'})
    getAccRecs({error, data}){
        console.log(data);
        if(data){
            this.accounts = data;
            this.error = undefined;
            toEmail = accounts.Floor_Plan_Providers__c;


        }
        else if(error){
            this.accounts = undefined;
            this.error = error;
        }
        

    }